BRATTLEBORO — Officials say high bacteria levels in some southeast Vermont swimming holes could be attributed to heavy rainfall.

Hi E. coli levels were found last week in 15 bodies of water in tests conducted by the Southeastern Vermont Watershed Alliance. The Brattleboro Reformer reported that the bodies of water were connected to the West, Rock, Williams, Middle Branch Williams and Saxtons rivers and the North Branch and Whetstone brooks.

The report said the elevated bacteria levels are often the result of heavy rainfall prior to test samples being taken. Similar findings were found after heavy rain in mid-June.

Group president Gloria Cristelli said E. coli are typically elevated after a rainstorm because animal waste is washed off the sides of a river and into the water.